CN113662740A

CN113662740A - Cold plate design in heat exchanger for intravascular temperature management catheter and/or heat exchange pad

Info

Publication number: CN113662740A
Application number: CN202110831366.3A
Authority: CN
Inventors: J·T·德布罗维克; C·W·彭德里; C·M·皮斯特
Original assignee: Zoll Circulation Inc
Current assignee: Zoll Circulation Inc
Priority date: 2015-03-31
Filing date: 2016-03-30
Publication date: 2021-11-19
Also published as: WO2016160960A1; JP2018509988A; EP3277232A4; JP6871861B2; JP2022180401A; CN107660142A; JP7137893B2; US20200261263A1; US20160287434A1; JP2021166712A; CA2980943A1; AU2016243186A1; US10537465B2; EP3277232A1; CN107660142B

Abstract

The cold plates (30, 32) through which the coolant flows define a slot (34) between the cold plates (30, 32) capable of receiving the cassette (50), wherein a sterile working fluid having a relatively low flow rate from the intravascular heat exchange catheter (12) or external pad (18) flows through the cassette (50). The slot (34) may have raised cavities (R1, R2) along the edges to allow the membrane of the cassette to expand and thus establish fluid supply and return channels.

Description

Cold plate design in heat exchanger for intravascular temperature management catheter and/or heat exchange pad

This application is a divisional application of the inventive patent application with application number 201680031530.X entitled cold plate design in a heat exchanger for intravascular temperature management conduits and/or heat exchange pads, filed by the applicant's zoll cycle service system company on PCT application PCT/US2016/024970, 30, 2016, entering the national phase on 29, 11, 2017.

Technical Field

The present application relates generally to heat exchange systems for controlling the temperature of a patient.

Background

Patient temperature control systems have been introduced to prevent patients in a neurological intensive care unit from becoming febrile due to subarachnoid hemorrhage or other neurological diseases such as stroke. In addition, the system has been used to induce mild or moderate hypothermia to improve the therapeutic efficacy of patients suffering from diseases such as stroke, cardiac arrest, myocardial infarction, traumatic brain injury, and high intracranial pressure. Examples of intravascular heat exchange catheters are disclosed in the following U.S. patents: no.7,914,564, No.6,416,533, No.6,409,747, No.6,405,080, No.6,393,320, No.6,368,304, No.6,338,727, No.6,299,599, No.6,290,717, No.6,299,599, all incorporated herein by reference.

An external patient temperature control system may be used. This system is disclosed in the following U.S. patents: no.6,827,728, No.6,818,012, No.6,802,855, No.6,799,063, No.6,764,391, No.6,692,518, No.6,669,715, No.6,660,027, No.6,648,905, No.6,645,232, No.6,620,187, No.6,461,379, No.6,375,674, No.6,197,045, and No.6,188,930 (collectively, "exterior gasket patents"), the entire contents of which are incorporated herein by reference. Also incorporated herein by reference is U.S. patent application 14/276,202 to the present assignee.

In USPN 7,070,612 of the present assignee, also incorporated herein by reference, a heat exchange console capable of receiving coils of a working fluid loop of both an intravascular heat exchange catheter and an external heat exchange pad has been described and patented. In summary, in all intravascular and external patient temperature control schemes, the temperature of the working fluid flowing through the catheter or pad is regulated by a heat exchange console based on feedback provided by the patient's actual body temperature, typically the core body temperature may be various rectal, esophageal, tympanic, or the like blood temperatures, e.g., vena cava, or the like. The working fluid temperature is regulated by thermally coupling the working fluid to heating and/or cooling elements in the console.

Disclosure of Invention

An apparatus comprising a plate assembly having a cassette slot configured to receive a membrane assembly of a cassette configured to receive a working fluid from an intravascular heat exchange catheter, external heat exchange pad, or other modality patient heat exchange member. The plate assembly also includes a rail receptacle spanning each side of the slot and configured to receive each side rail (rail) of the cassette. At least a first bulge cavity, receptacle or groove is formed inside the first rail receptacle. The first bulge cavity may have a diameter or width at its widest point that is greater than the width of the slot.

In an example, a second projection cavity, receptacle or groove is formed inside a second rail receptacle. The second cavity may have a diameter or width at its widest point that is greater than the width of the slot. Both lug cavities engage with each side of the groove. In particular embodiments, the first and/or second projection cavity may have a diameter or width at its widest point that is less than the transverse diameter or width of the first or second rail receiving portion and/or greater than the width of the slot.

When the cassette is engaged with the apparatus by arranging the membrane assembly in the slot and the side rails of the cassette in the rail receptacles, a first portion of the membrane, e.g., adjacent an edge of the membrane assembly, inside the side rails of the cassette can expand into the first bulge cavity when the membrane assembly is filled with working fluid, thereby establishing an enlarged fluid passage along a vertical side edge of the membrane assembly. The first projection cavity may extend substantially the entire length of the first rail receptacle and may be circular or semi-circular, diamond shaped or otherwise shaped.

In another aspect, an apparatus includes a plate assembly, wherein the plate assembly further includes a separation plate having a first flow path formed on a first side of the separation plate and a second flow path formed on a second side of the separation plate opposite the first side. The first flow path is configured to receive coolant from the compressor through the compressor, while the second flow path is configured to receive water or other fluid from the patient heat exchange pad or from a water source or other fluid source other than the pad. The first backing plate abuts the first side of the divider plate and the second backing plate abuts the second side of the divider plate. The lumen is bordered by a first footplate opposite the separator plate and is configured to receive a cassette configured to hold a working fluid circulating through the intravascular heat exchange catheter.

In some examples, the first and second backing plates abut the first and second sides of the separator plate along the entire or substantially the entire first and second sides of the separator plate, while only the first and second flow paths establish a cavity through which the respective fluids can flow. One or both of the flow paths may be serpentine shaped.

With this structure, the coolant in the first flow path can exchange heat with the fluid in the cartridge disposed within the cavity. Likewise, the coolant in the first flow path can exchange heat with the fluid in the second flow path via the partition plate. Further, the fluid in the second flow path can exchange heat with the fluid in the cartridge disposed in the chamber through the partition plate and the first shim plate. Coolant flow through the first flow path may be established to maintain some liquid phase throughout the cross-section of the coolant through the first flow path. In particular embodiments, other plate assemblies are contemplated which may have one or more flow paths configured for receiving water or other fluids from a patient heat exchange pad or from another source of water or other fluid (e.g., a source of fluid that has been cooled or heated), wherein the fluid or water in the flow path is capable of exchanging heat with fluid in a cartridge disposed in the plate assembly.

In another aspect, a heat exchange system that exchanges heat with a working fluid from an intravascular heat exchange catheter or from an external heat exchange pad or other form of patient heat exchange member includes at least one compressor configured to circulate a coolant through the system to exchange heat with the working fluid. At least one conduit, pipe, or interface (port) is configured to receive exhaust heat from the compressor and direct the exhaust heat to the patient.

In particular embodiments, a heat exchange system that exchanges heat with a working fluid from an intravascular heat exchange catheter or from an external heat exchange pad or other modality patient heat exchange member may include a plate assembly having one or more flow paths. The flow path may be configured to receive a coolant through the flow path, wherein a flow of coolant through the flow path is established or adjusted to maintain at least some liquid phase throughout a cross-section of the coolant through the flow path or cold plate and the coolant exchanges heat with the working fluid.

The details of the various embodiments, both as to structure and operation, described herein can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which:

drawings

FIG. 1 is a schematic diagram of a non-limiting system according to an embodiment;

FIG. 2 is a perspective view of an example working fluid cartridge holder portion of a heat exchange system;

FIG. 3 is a perspective view of one half of the cartridge holder shown in FIG. 2, assuming that the opaque metal inner surface is shown transparently to show serpentine coolant channels;

FIG. 4 is a perspective view of an example working fluid cartridge configured to engage the cartridge holder shown in FIGS. 2 and 3;

FIG. 5 is a cross-sectional view of FIG. 2;

FIG. 6 is a cross-sectional view of the alternative embodiment as seen along line 5-5 of FIG. 2;

FIG. 7 is a top view of an alternative configuration of the cartridge slot shown in FIG. 2; and

FIG. 8 is a cross-sectional view of an alternative cold plate embodiment in which coolant flows through concave flow paths (concave channels) on one side of the divider plate and water from the external cooling pad or water from the cold fluid source flows through concave flow paths on the opposite side of the divider plate;

fig. 9 is an exploded view of a cold plate embodiment.

Detailed Description

Referring first to fig. 1, in accordance with the present principles, a system 10 may include an intravascular heat exchange catheter 12 controlled by a control system 14 to control patient temperature, e.g., to prevent fever in a patient 16 or to induce therapeutic hypothermia in the patient 16. In the conduit, a working fluid or coolant, such as, but not limited to, saline, circulates in a closed loop (typically affected by a pump "P" in the control system) from the control system 14, through the fluid supply line L1, through the conduit 12, and back to the system 14 through the fluid return line L2, such that no working fluid or coolant enters the body. Any of the catheters disclosed above or in the following U.S. patents, the entire contents of which are incorporated herein by reference, may be used: USPN 6,419,643, 6,416,533, 6,409,747, 6,405,080, 6,393,320, 6,368,304, 6,338,727, 6,299,599, 6,290,717, 6,287,326, 6,165,207, 6,149,670, 6,146,411, 6,126,684, 6,306,161, 6,264,679, 6,231,594, 6,149,676, 6,149,673, 6,110,168, 5,989,238, 5,879,329, 5,837,003, 6,383,210, 6,379,378, 6,364,899, 6,325,818, 6,312,452, 6,261,312, 6,254,626, 6,251,130, 6,251,129, 6,245,095, 6,238,428, 6,235,048, 6,231,595, and ppus 6,231,595, 6,231,595. The catheter 12 may be placed in the venous system, for example, in the superior vena cava or inferior vena cava.

Instead of or in addition to the catheter 12, the system 10 may include one or more pads 18 that are positioned against the external skin of the patient 16 (only one pad 18 is shown for clarity). Without limitation, the gasket 18 may be any of the gaskets disclosed in the exterior gaskets patents discussed above. The temperature of the pad 18 can be controlled by the control system 14 to exchange heat with the patient 16, including inducing therapeutic mild or moderate hypothermia in patients suffering from conditions that can be alleviated by hypothermia, such as cardiac arrest, myocardial infarction, stroke, high intracranial pressure, traumatic brain injury, or other conditions. The shim 18 may receive working fluid from the system 14 via a fluid supply line L3 and return the working fluid to the system 14 via a fluid return line L4.

The control system 14 may include one or more microprocessors 20 that receive the target and patient body temperatures as inputs and controls, and may additionally include a pump "P", a coolant compressor 22, and/or a bypass valve 24 that can be opened to allow coolant to bypass the condenser. The coolant circulates through the heat exchanger in the control system 14 and is further described below. The processor 20 may access instructions on the computer memory 26 that configure the processor 20 to execute the logic discussed below. The computer memory 26 may be, for example, a disk or solid state memory.

Warm exhaust air from the compressor 22 or fan may be directed through the conduit 27 to warm the patient 16. Although fig. 1 shows conduit 27 as having an open end adjacent the patient, it should be understood that conduit 27 may direct air into a blanket, tent, or other covering that partially or completely surrounds the patient.

In other embodiments, heat generated by the system 10, e.g., by a compressor or any other component of the system, may be transferred or directed to the surface of the patient to warm the patient before, after, or during cooling of the patient with the heat exchange conduit or pad.

Fig. 1 also shows that in the absence of coolant for the compressor 22 or the absence of electrical power or other reasons for not being able to circulate coolant through the system to cool the working fluid of the conduit 12, if it is still desired to cool the working fluid of the conduit 12, a source 28, such as a cold water bath, may be connected to the shim fluid lines L3 and L4 to provide cold fluid to the system to cool the conduit working fluid. Details are discussed further below.

FIG. 2 illustrates a portion of an example heat exchanger in the control system 14 that includes at least two

cold plates

30, 32, the

cold plates

30, 32 defining a cassette slot 34 therebetween. In one embodiment, the width "W" of the groove 34 is less than forty mils (0.040 "), and may be between twenty-nine mils and thirty-one mils (0.029" -0.031 "). In other embodiments, the width of the groove is between 0.020 "and 0.070" mils. In a particular example, the width "W" may be thirty mils. As explained in further detail below, a coolant chamber may be created in the tank 34 to receive a heat exchange member such as, but not limited to, a cassette through which working fluid flows from an intravascular heat exchange catheter, external heat exchange pad, external cooling pad, or other form of patient heat exchange member. Because the heat exchange occurs through the walls of the heat exchange member, the working fluid from the conduit or gasket does not come into contact with any surfaces or fluids in the heat exchanger of the control system 14 outside the walls of the heat exchange member. In this way, the working fluid, typically saline in a non-limiting example, circulating through the intravascular catheter or pad can be maintained sterile. Therefore, attention will first be focused on the coolant chamber created by the groove 34.

The

cold plates

30, 32 may be made of metal or other thermally conductive material, and as shown may be rectilinear and indeed may be near square. The

cold plates

30, 32 may abut one another along the left and right side walls 36 with the elongated vertical box frame receivers R1 and R2 located immediately inboard of each side wall 36 and the slot 34 extending between the walls 36 and terminating in receivers R1, R2 as shown. The frame receiving portions R1, R2 may be wider than the slot 34. In the example shown, the coolant inlet and

outlet pipes

38, 40 extend through the at least one cold plate 32 to communicate coolant from the compressor 22 into the coolant passages in the cold plates, which creates a second coolant chamber (and which is in thermal contact with) outside of the first coolant chamber created by the slots 34. Each cold plate may have its own coolant inlet and outlet tubes, or each cold plate may have an inlet or outlet, for example where the coolant passages of the cold plates are in fluid communication with each other, or in the illustrated embodiment, only one cold plate may be formed with coolant inlet and outlet tubes while the other cold plate is thermally coupled to the former cold plate with coolant flowing therethrough, and/or receives coolant from the other cold plate through passages formed through one or both of the side walls 36.

In one example, as shown, shim working fluid inlet P_inAnd an outlet P_outMay also be formed in at least one cold plate. As discussed in more detail below, working fluid from the shim 18 or from the cold fluid source 28 via lines L3 and L4 or other lines may be diverted into the shim working fluid inlet_PinAnd an outlet P_outTo exchange heat with the coolant or, in some cases, working fluid from the conduit flowing through the cold plate. Additionally, one or more electric heaters 41 may be mounted on one or both cold plates to heat the cold plates in order to provide a warm working fluid. Or to warm the cold plates, a bypass valve 24 (fig. 1) may be opened as the gaseous coolant circulates through the system to allow the hot gaseous coolant from the compressor to bypass the condenser.

FIG. 3 shows a detail of an example cold plate 32, assuming the interior surface is viewed transparently, it being understood that the interior surface is typically metal and thus the serpentine coolant channel 42 shown in FIG. 3 is typically not visible to the human eye. In any case, the example coolant channels that fluidly communicate the coolant inlet 38 with the coolant outlet 40 may be serpentine in shape as shown, or may be some other shape or pattern, such as a herringbone pattern, a wavy pattern, or a coiled, curved, or serpentine pattern, or a configuration having one or more curves, turns, and/or bends, or the like.

Fig. 4 illustrates an example working fluid cartridge 50 in accordance with the present principles. The cassette 50 is configured to fit snugly into the slot 34 defined between the

cold plates

30, 32 and the cassette frame receptacles R1, R2. In operation, a working fluid, such as saline, from a patient-engageable heat exchange member, such as the conduit 12 or an external pad, flows through the cassette 50 while the working fluid exchanges heat with the coolant in the cold plate. In an exemplary embodiment, the cassette 50 is a low cost disposable item that can contain, for example, sterile saline that is circulated through the catheter 12 or external pads. The cassette is placed by the medical caregiver in the slot 34 between the

cold plates

30, 32 and as the working fluid flows through the membrane portions, which define the space or working fluid chamber through which the example saline flows, expand into thermal contact with the

cold plates

30, 32.

In the example shown, the cartridge 50 includes a frame 52 defining a perimeter and a preferably rectilinear opening bounded on at least three sides by the perimeter of the frame as shown. In the non-limiting example shown, the frame comprises an elongated parallelepiped-shaped top rail 53 and elongated parallelepiped-shaped left and right side rails 54 parallel to each other and perpendicular to the top rail 53. An exemplary frame 52 may have a metal band or bottom rail 51 opposite the top rail and connected to left and right side rails 54 to support the membrane and to cause the membrane to be placed in a bi-directional tension (biaxial tension). In any event, the example frame 52 is rectilinear and is configured to be closely received between the two

cold plates

30, 32, while the side rails 54 are slidably engaged with the frame receptacles R1, R2 between the

cold plates

30, 32, with the below-described membrane assemblies passing through the slots 34 closely juxtaposed with the coolant flow paths in the cold plates. In certain variations, receptacles R1, R2 may be keyed or each have a different shape corresponding to the shape or configuration of the side rails of the cassette. This helps to ensure that the cassette is inserted into the slot and receptacle in the correct orientation, providing guidance to the user.

In fig. 4, the top rail 53 of the frame in the example shown is formed with a fluid inlet 56 arranged with an inlet pipe 58 and a fluid outlet 60 arranged with an outlet pipe 62. The inlet and outlet each create a respective fluid passage through the frame into the opening. The inlet and

outlet tubes

58, 62 may be joined with fluid return and supply lines L1, L2 associated with the catheter 12. One or both of the

tubes

58, 62 may terminate slightly below the headrail 53, flush with the bottom of the headrail, or may extend any desired length down to the bottom of the assembly, i.e., one or both of the

tubes

58, 62 may extend almost the entire length of the left and right side rails 54, terminating slightly above the bottom seam of the membrane assembly described below. In particular embodiments, the inlet and outlet tubes may extend a sufficient length to allow the tubes to engage features or components in or on the cold plate, e.g., at least a portion or end section of the tubes may be seated in a groove or step located on an interior wall or face of the cold plate. The inlet and outlet tubes may be positioned such that they mate or line up with the raised cavities in the cold plate. This orientation may help minimize or prevent the membrane assembly from bulging outward in an uncontrolled or less controlled manner, which may lead to breakage. In particular embodiments, the inlet and

outlet pipes

58, 62 or separate inlet and outlet pipes may be engaged with the fluid return and supply lines L3, L4 associated with the external gasket.

In practice, a membrane assembly 64, such as a polymer membrane assembly, is attached to the frame 52, as shown to close off the opening bounded on four sides by the frame. The diaphragm assembly 64 includes a first diaphragm 66 and a second diaphragm 68, the first diaphragm 66 being parallel to the second diaphragm 68 and in close proximity to the second diaphragm 68, leaving a space between the first and

second diaphragms

66, 68 to create a working fluid chamber. The fluid inlet 56 and fluid outlet 60 communicate with the spaces between the

membranes

66, 68. At least one, and preferably both, of the

membranes

66, 68 are stretch disposed in the opening. The space between the membranes is expandable when filled with a working fluid.

In one example, each film is no greater than two mils (0.003 ") thick, and preferably has a thickness between one and three mils (0.001" -0.003 "), inclusive. In particular embodiments, each film may have a thickness between one and five mils (0.001 "-0.005"). The example membranes 66, 68 are coextensive (co-extensive) with the opening and are nearly square like the opening, with the top and bottom edges of the example membranes having lengths approximately equal to the lengths of the left and right edges of the membranes (within ± 10%, more preferably within ± 5%). In other embodiments, instead of square aspect ratios (1:1), aspect ratios up to 1:1.5 may be used. The working fluid chamber between the membranes is also rectilinear and in particular embodiments there is no obstruction between the membranes, meaning that the working fluid chamber is perfectly rectilinear approaching a square chamber.

Because of the thinness of the

membranes

66, 68, the proximity of the

cold plates

30, 32 to each other, and the proximity of the membrane assemblies therebetween when the cassette is engaged with the cold plates, the system shown in the figures provides a low impedance to heat transfer between the coolant circulating in the cold plates and the working fluid circulating between the

membranes

66, 68. The working fluid chamber between the membranes expands due to the back pressure created by the working fluid flow, eliminating or reducing the need for a moving mechanism in the cold plate. In addition, the narrow slot 34 between the two cold plates provides better heat transfer by reducing the length of the conductive path between the cold plates and the working fluid. The frame allows for easy handling, such as insertion/removal of the cassette from the cold plate.

For example working fluid chambers between the

membranes

66, 68 having a width-to-length aspect ratio of approximately 1:1 (i.e., square or nearly square), the amount of backpressure required to direct the working fluid through the heat exchanger is reduced as compared to configurations that are not square enough. This reduces the amount of work that the working fluid pump must perform, which reduction is desirable for two reasons. One is that because the pump can be disposable, the lower performance requirements translate into a lower cost disposable and quieter system. For example, peristaltic roller pumps provide quiet operation and low cost disposable elements, but operate most efficiently only when moderate pressure is required. And secondly, the heat transferred into the working fluid by the pump is reduced because the work of the working fluid pump is reduced. Furthermore, a low width/length aspect ratio results in a slower working fluid velocity that reduces the amount of mixing, but this otherwise desirable (from a heat exchange perspective) effect is negligible in this example system, since the Reynolds numbers (Reynolds numbers) are typically < 1000, which indicates a laminar flow regime. In addition, the low width/length aspect ratio significantly reduces the number of bends (or "corners") in the fluid flow path. These bends are areas of mixed fluid that promote heat transfer. Without the bend, a fluid boundary layer is established. However, by maintaining narrow slots between the cold plates, this effect is offset here. The primary heat transfer method in this approach is by conduction, but the conduction path length (and hence the boundary layer) is small, resulting in a relatively high heat transfer rate.

In particular embodiments, the surface of the cold plate facing the cartridge membrane may be coated with a non-adherent ("peel-off") and/or hydrophobic coating to aid in removal of the cartridge after use. In some examples, removal may be difficult due to back pressure from the brine fluid flow pressing the heat exchange membrane against the cold plate surface throughout use (e.g., up to 7 days), causing the membrane to adhere to the cold plate. The large surface area may result in a strong force that is difficult for the user to overcome. In addition, there may be a thin film of water (due to leakage, condensation) between the membrane and the cold plate surface resulting in additional capillary forces that in some cases may be difficult to overcome and can lead to damage to the cartridge or cold plate making extraction difficult. Non-adherent and/or hydrophobic coatings are moderated by minimizing capillary forces. In addition, the water film may dry completely, potentially leading to Van der Waals adhesion (Van der Waals adhesion). The non-adherent aspect of the coating prevents this from occurring. Fluoropolymer coatings provide both hydrophobic and release (non-stick) characteristics and may be used with other non-stick and/or hydrophobic materials or coatings.

In a particular example, the

membranes

66, 68 are stretched under tension during assembly to the frame, preferably bi-directional tension (i.e., under tension between the top and

bottom rails

53, 51 and between the left and right side rails 54). The tension can be maintained over the shelf life of the product. The pre-tensioning minimizes wrinkles in the material, which is beneficial because wrinkles can impede working fluid flow and create air gaps that reduce heat transfer between the working fluid and the cold plate. The pleats can also complicate insertion of the membrane assembly into the narrow slot 34.

To establish pre-tensioning of the membrane, the frame may be made in two frame halves, posts such as threaded fasteners or the like may extend transversely to one half of the frame, and the

membranes

66, 68 are stretched over the posts and the posts are received by holes made in the membranes. The other half of the frame is then positioned so that the rectilinear boundary portion of the membrane assembly is sandwiched between the two frame halves, with a closure, such as a respective nut, engaging the post to hold the frame halves together, while the membrane assembly is held in tension between the frame halves. Optionally posts (e.g. using press-fit posts) may be located in one or more of the frames to hold the frame halves together. The post may be made of plastic or other suitable material. Fig. 4 shows that the working fluid chamber is closed at the bottom by a bottom seam 74A of the membrane module, wherein the bottom seam 74A is part of the boundary portion. In addition to applying tension to avoid wrinkles in use, additional posts may be used to avoid wrinkles during welding, improving the quality of the welded joint.

In the border portion, the

membranes

66, 68 may be reinforced with at least one and preferably multiple layers of polymer film to create a welded seam through which (at the side of the membrane assembly) post holes are formed, allowing for easier processing. By placing the reinforcement layer only at the boundary portions, the central "window" of the membrane assembly is comprised of only a single layer of thin film between the working fluid and one of the

cold plates

30, 32 to minimize obstruction to heat transfer. A die cut reinforcement layer may be used that reinforces the entire perimeter with a piece of material.

In some examples, the

polymer films

66, 68 are highly stretchable with an elongation of at least greater than 25%. This allows the membrane to change from the empty flat state shown in fig. 4 to an expanded shape (within the slot 34 between the cold plates) without wrinkling. It also allows the film to easily conform to features on the face of the cold plate.

Additionally, the membrane may be made of a material that can also be made into a tube. The tubes such as the inlet and

outlet tubes

58, 62 shown in fig. 4 can then be heat welded (e.g., using RF sealing) to the membrane, which is more reliable and faster than adhesive bonding. Because the

cold plates

32, 34 and the frame 52 provide support for the expanding membrane assemblies, allowing the membrane assemblies to withstand the pressure created by the working fluid flowing between the membranes, the

membranes

66, 68 need not provide their own lateral support. Structural features such as raised bumps, concavities, raised ribs, etc. may be located on the cold plate to optimize heat transfer. For example, the face of the cold plate may be corrugated or include features (cut-outs or protrusions) that provide increased surface area to increase or optimize heat exchange or transfer between the membrane and the cold plate. The features may have different shapes or patterns, such as serpentine, coiled, curved, or serpentine patterns or shapes, or may include configurations having one or more curves, turns, and/or bends. This may be economically advantageous because the cold plate may be a reusable component. The manifold (manifold) may be cut into cold plates to even out the distribution of the brine flow.

Having described an exemplary non-limiting heat exchange combination of the structure between the heat exchanger in the control system 14 and the sterile working fluid in the intravascular temperature control catheter 12 or spacer 18, attention will now be directed to fig. 5, which illustrates an exemplary embodiment of an additional coolant chamber in the cold plate through which heat exchange is conducted with the working fluid, including the non-sterile working fluid, from the external heat exchange spacer 18. Note that the plate structure shown in fig. 5 is preferably metal or other material having high thermal conductivity.

As shown, although the

cold plates

30, 32 are generally referred to as "plates" 30 and 32 in the following discussion, the

cold plates

30, 32 may be a multi-plate assembly defining a multi-fluid chamber. In the non-limiting example shown, the coolant inlet and

outlet tubes

38, 40 extend through the outer wall 80 and the partition wall 82 of the cold plate 32 to communicate coolant from the compressor 22 into the coolant passages in the cold plate, which establishes a coolant chamber 42 bounded by the partition wall 82 and the inner wall 84. On the other side of the inner wall 84 is the working fluid cartridge slot 34. As previously set forth, each cold plate may have its own coolant inlet and/or outlet tube, or only one cold plate may be formed with coolant inlet and outlet tubes while the other cold plate is thermally coupled to the aforementioned cold plate with coolant flowing therethrough and/or receives coolant from the other cold plate through channels formed therebetween. In the illustrated example, the

cold plates

30, 32 are thermally coupled by uninterrupted portions of the side walls 36 (fig. 2), the common bottom wall 86 (fig. 5), and the top wall 88 formed with the slot 34.

In some examples, the

cold plates

30, 32 are mirror images of each other. In the example of FIG. 5, the coolant chambers 42 in the left hand cold plate (32) are in fluid communication with the coolant chambers 94 in the right hand cold plate 30 via the coolant supply and return passages 90, 92. Thus, the coolant chambers of the cold plates straddle the cassette slot 34 and are separated from the cassette slot 34 by the respective inner walls 84, with coolant flowing serially through the left and right coolant chambers 42, 94: first from the coolant inlet pipe 38 into the left coolant chamber 42, then through the coolant supply passage 90, the right hand side coolant chamber 94, back through the coolant return passage 92, and out of the coolant outlet pipe 40. When two coolant chambers are provided as in the illustrated example, this increases the flow rate of coolant fluid through the

coolant chambers

42, 94.

In contrast, the shim working fluid flow paths may be routed in parallel to the fluid flow through left and right

shim fluid chambers

106, 108 which straddle the coolant chamber as shown and are separated from the coolant chamber by respective partition walls 82. In the non-limiting example shown, fluid from the external shim flows through the shim working fluid inlet P_inInto an inlet plenum 100 formed in the bottom wall 86. The fluid flows in parallel through the

inlet ports

102, 104 into the left and right shim working

fluid chambers

106, 108. Fluid exits the shim working fluid chamber through an upper plenum 110 formed in the top plate 88 and exits the working fluid outlet P_outAnd out back to the outer pad. This example parallel fluid flow reduces back pressure in the shim working fluid system.

Note that the serial fluid flow through the coolant chamber and the parallel fluid flow through the shim working fluid chamber described above are exemplary only and not limiting. Thus, fluid flow through the shim working fluid chambers may be in series and/or fluid flow through the coolant chambers may be in parallel. It is also noted that the particular example passage configuration illustrated and described is merely one example of a passage fluid through the multi-chamber

cold plates

30, 32.

In fact, FIG. 6 shows a system similar to that shown in FIG. 5, except that the fluid flow through the coolant chambers is in parallel. Both coolant chambers may be in communication with a coolant inlet plenum 200, wherein coolant flows through the plenum 200 into each of the

coolant chambers

42, 94 in parallel. Further, both coolant chambers may be in communication with a coolant outlet plenum 202, wherein coolant exits each of the

parallel coolant chambers

42, 94 back to the compressor through the plenum 202.

It can now be appreciated that in the intravascular heat exchange mode, the working fluid flowing through the cassette 50 disposed in the slot 34 from the conduit 12 exchanges heat with the coolant in the

coolant chambers

42, 94 through the respective inner walls 84. Because the conduit working fluid flows through the cassette 50, the conduit working fluid does not contact any portion of the cold plate heat exchanger. In this manner, the catheter working fluid maintains its sterility and is enclosed in a closed fluid circuit to withstand, for example, up to seventy pounds per square inch (70psi) of circulating fluid pressure.

On the other hand, because the shim working fluid is separated from the patient by an external shim, sterility of the shim working fluid may not be required, in which case the shim working fluid may directly contact the divider plate 82 in the

cold plates

30, 32 to exchange heat with the coolant in the

coolant chambers

42, 94.

Fig. 7 shows an alternative cold plate assembly 700 having a cassette slot 34 'and rail receivers R1' and R2 'for receiving the straddle slot 34' of the side rail of the cassette 50, with the receivers and slots being substantially identical in construction and function to the corresponding parts shown in fig. 2. Unlike fig. 2, however, fig. 7 shows that inside each of the receivers R1 ', R2', the cold plate assembly 700 is formed with each projection or expansion cavity 702, receiver or groove that may extend substantially the entire length (more or less millimeters) of the side rail receiver. In an embodiment, each relief cavity 702 may be circular or semi-circular (although other shapes may be used). The bulge cavity may be defined between the cold plates 30 ', 32'. The cold plate 30 'and/or 32' may form a cavity or recess in its inner wall. The cavity or groove may be separated or spaced from the side rail receptacle, such as by a land (plating) or other segment of the cold plate, such that the boss cavity is separated or spaced from the side rail receptacle. This may help minimize or prevent the membrane assembly from expanding into the side rail receptacle when the membrane is filled with working fluid. The boss cavities engage or connect with the slots 34 'at the apex of the semi-circle, e.g., the semi-circular boss cavities may engage the slots 34'. As shown in fig. 7, each lug cavity 702 at its widest point may have a width W or diameter (e.g., a diameter of a circle or semi-circle) that is less than the lateral diameter or width W2 of the rail receiving portion but greater than the width W3 of the slot 34'. In other embodiments, the lug cavity may be immediately inside the rail receptacle.

With this arrangement, when the cassette 50 is engaged with the cold plate assembly 700 with the membrane assembly 64 disposed in the slot 34 ' and the cassette rails disposed in the rail receptacles R1 ', R2 ', portions of the membrane assembly, such as the portions near the edges of the membrane assembly 64 and inside the side rails of the cassette, can expand into the bulge cavity 702 as the membrane assembly 64 fills with working fluid. This establishes enlarged fluid supply and return passages along the vertical side edges of the membrane module 64. In this manner, the working fluid entering the top of the cassette 50 along one side rail flows primarily down the fluid supply channel of the portion of the membrane assembly that has expanded within the boss cavity. The fluid supply on the cassette 50 may be positioned such that the fluid supply on the cassette 50 is concentric or in-line with the boss cavities. As fluid flows down the feed channel from the fluid feed channel, portions of the feed fluid gradually emerge that flow throughout the membrane assembly to the fluid return channel established by the portion of the membrane assembly that has expanded within the bulge cavity 702 immediately adjacent the fluid return tube on the cassette 50.

Fig. 8 illustrates an alternative cold plate 800 that is substantially identical in construction and operation to the cold plate illustrated in fig. 5 and 6, with the following exceptions. The separator plate 802 may have flow paths 804, 806 (which may be configured the same as the serpentine flow path 42 shown in fig. 3 or in another pattern or shape, e.g., having one or more curves, turns, and/or bends), wherein the

flow paths

804, 806 are formed on respective side surfaces of the separator plate 802. As with the other cold plate structures shown and discussed herein, the divider plate 802 is highly thermally conductive and may be made of metal, suitable thermoplastics, or other heat transfer materials.

The left and

right backing plates

808, 810 can abut the left and right sides of the divider plate 802 along the entire sides of the divider plate, while only the

flow paths

804, 806 establish chambers through which the respective fluids can flow. (FIG. 9 shows an exploded view of 800). Thus, coolant may flow through the left flow path 804 between the divider plate 802 and the left backing plate 808, and water from the lines L3, L4 of fig. 1, for example, from a patient heat exchange pad or from a source other than a pad, such as a water reservoir that may be used as a heat storage unit, may flow between the divider plate 802 and the right backing plate 810 through the right flow path 806. In this configuration, the cartridge slot 34' may be located on the opposite side of the left backing plate 808 from the divider plate 802 as shown. With this structure, not only can the coolant be able to exchange heat with saline in the sterile conduit 12 in the cassette or non-sterile fluid from the gasket 18 or, optionally, gasket fluid in the cassette, but in the event that coolant is not available or only battery power is available (so the compressor 22 is not actually on-line), water from the cold fluid source 28 (shown in fig. 1) or water storage (e.g., where the water was previously cooled by the compressor) can be diverted into the right flow path 806 to provide some heat exchange with the cassette 50 in the trough 34' across the divider plate 802 and the left gasket 808.

In this particular embodiment, the various cold assemblies described herein may be assembled by brazing the plates together, for example in a furnace, and/or by vacuum brazing, for example. The plates may also or alternatively be connected by mechanical fasteners and sealed with O-rings, and/or may be sealed using gaskets.

If desired, the coolant may be allowed to warm up to heat the present cold plate when, for example, a target temperature is reached, avoiding patient overcooling and/or running the system pump backwards to shorten the equalization intervals (equalization stops) of the x-probe. Additionally, the coolant flow may be established or adjusted to maintain at least some liquid phase of the coolant for substantially all or a portion of the time during which the coolant flows or traverses the channels of the cold plate to facilitate heat exchange, wherein the coolant may exchange heat with working fluid from the intravascular heat exchange catheter and/or external heat exchange pad.

As discussed above, during internal cooling, the use of the conduit 27 of FIG. 1 may allow the patient 18 to be warmed externally by the discharge heat from the compressor 22 for comfort, or to re-warm the patient after cooling. In particular embodiments, heat generated by the system 10, e.g., by a compressor or any other component of the system, may be transferred or directed to the surface of the patient to warm the patient before, after, or during cooling of the patient with heat exchange tubes or pads, e.g., to prevent or reduce shiver. In certain variations, heat may be directed to the patient via a warmer or other hot air blanket or tent used in the hospital to help keep the patient's skin warm. Other mechanisms or ways of warming the patient include, but are not limited to: placing or including an electrical heating element within the spacer; warming the patient with radiant heat lamps; directing warm air from a fan on the console or system that removes heat from the compressor to or toward a surface of the patient; and providing or including a third fluid circuit containing warm fluid in the system.

Although various embodiments of cold plate designs in heat exchangers for intravascular temperature management conduits and/or heat exchange pads are shown and described in detail herein, the scope of the present invention is not limited in any way except as by the appended claims. The components included in one embodiment can be used in other embodiments in any suitable combination. For example, any of the various components described herein and/or depicted in the figures may be combined, interchanged, or excluded from other embodiments.

A "system having at least one of A, B and C" (likewise, "a system having at least one of A, B or C" and "a system having at least one of A, B, C") includes systems having a alone, B alone, C, A and B alone, a and C together, B and C together, and/or A, B and C together, and the like.

Claims

1. An apparatus, comprising:

a plate assembly having a cassette slot configured to receive a membrane assembly of a cassette, wherein the membrane assembly is configured to receive a working fluid from an intravascular heat exchange catheter or heat exchange gasket, the plate assembly further comprising a rail receptacle spanning each side of the slot and configured to receive each side rail of the cassette, wherein

At least a first cavity is formed inside a first of the rail receiving portions, the first cavity having a width at its widest point that is greater than the width of the slot.

2. The device of claim 1, comprising a second cavity formed inside a second one of the rail receptacles, the second cavity having a width at its widest point that is greater than a width of the slot.

3. The apparatus of claim 1, wherein when the cassette is engaged with the apparatus by disposing the membrane assembly in the slot and the side rail of the cassette in the rail receptacle, a first portion of the membrane assembly inside the side rail of the cassette is able to expand into the first cavity when the membrane assembly is filled with working fluid, thereby establishing an enlarged fluid passageway along a vertical side edge of the membrane assembly.

4. The device of claim 1, wherein the first cavity extends substantially the entire length of the first rail receptacle.

5. The device of claim 1, wherein the first cavity is circular or semi-circular.

6. An apparatus, comprising:

a plate assembly, comprising:

a partition plate having a first flow path formed on a first side thereof and a second flow path formed on a second side thereof opposite to the first side;

the first flow path is configured to receive coolant from a compressor through the compressor, the second flow path is configured to receive fluid from a patient heat exchange pad or from a fluid source other than the pad;

a first backing plate abutting the first side of the divider plate;

a second backing plate abutting the second side of the divider plate; and

a lumen bordering the first footplate opposite the separator plate and configured to receive a cassette, wherein the cassette is configured to hold a working fluid circulating through an intravascular heat exchange catheter.

7. The apparatus of claim 6, wherein the first pad abuts the first side of the divider plate along the entire first side of the divider plate, the second pad abuts the second side of the divider plate along the entire second side of the divider plate, and only the first and second flow paths of the divider plate establish a cavity through which each fluid can flow.

8. The device of claim 6, wherein at least the first flow path is serpentine shaped.

9. The apparatus of claim 6, wherein the coolant in the first flow path is capable of exchanging heat with a fluid within a cartridge disposed in the cavity.

10. The apparatus of claim 6, wherein the coolant in the first flow path is capable of exchanging heat with the fluid in the second flow path through the divider plate.